Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
The average person's skin weighs twice as much as their brain.
131
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73
All the chemicals in a human body combined are worth about 6.25 euro (if sold separately).
266
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118